Windows Media Center does not start - no mscoree.dll

Few days ago when i started Windows Media Center to watch TV from TV tuner windows displayed error message, that mscoree.dll is incorrect and needs to be fixed, so i've started chkdsk as it suggested and since then i can't run WMC. It says, that it can't find mscoree.dll file.

File itself exists and is located in windows/system32 directory and have ~400kb. i've tried to copy that file from my 2nd computer, but that didn't help.

SFC /scanall didn't help. It fixed some files (after granting permission) but not this one (it said it fixed it, but error still appears).

If i copy mscoree.dll into windows/ehome directory, when starting Media Center i don't see any error message, but nothing happens, process is terminated immediately without any error message.

Is there any other way to check for missing/invalid files? In old times (somewhere around last ice age ), for example on windows XP, you could start installer from CD and tell it to fix instalation, but i don't see anything similar on Win 7. Windows Restore sees only points from today and yesterday and nothing older, so it will not help.